NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Interaction of Porosity with an Advancing Solid/Liquid Interface: a Real-Time InvestigationProblems associated with formation of porosity during solidification continue to have a daily impact on the metal forming industry. Several past investigations have dealt with the nucleation and growth aspects of porosity. However, investigations related to the interaction of porosity with that of a solidification front has been limited mostly to organic analogues. In this paper we report on real time experimental observations of such interactions in metal alloys. Using a state of the art X-Ray Transmission Microscope (XTM) we have been able to observe and record the dynamics of the interaction. This includes distortion of the solid/liquid interface near a poro.sity, solute segr,egation patterns surrounding a porosity and the change in shape of the porosity during interaction with an advancing solid/liquid interface. Results will be presented for different Al alloys and growth conditions. The experimental data will be compared to theory using a recently developed 2D numerical model. The model employs a finite difference approach where the solid/liquid interface is defined through the points at which the interface intersects the grid lines. The transport variables are calculated at these points and the motion of the solidification front is determined by the magnitude of the transport variables. The model accounts for the interplay of the thermal and solutal field and the influence of capilarity to predict the shape of the solid/liquid interface with time in the vicinity of porosity. One can further calculate the perturbation of the solutal field by the presence of porosity in the melt.
Document ID
19990103106
Acquisition Source
Marshall Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Sen, S.
(Universities Space Research Association Huntsville, AL United States)
Kaukler, W.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Catalina, A.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Stefanescu, D.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Curreri, P.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Date Acquired
August 19, 2013
Publication Date
January 1, 1999
Subject Category
Metallic Materials
Meeting Information
Meeting: Modeling of Casting and Solid, Processes
Location: Seoul
Country: Korea, Republic of
Start Date: September 5, 1999
Funding Number(s)
CONTRACT_GRANT: NCC8-66
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available